The present disclosure relates to an output circuit. Mobile communication devices such as a mobile phones employ a power amplification circuit to amplify power of radio frequency (RF) signals to be transmitted to a base station. The power amplification circuit includes a bias circuit for supplying a bias voltage or bias current to an amplifier. In some cases, the power amplification circuit includes a plurality of amplifiers corresponding to a plurality of operation modes. In this power amplification circuit, the output path for the bias voltage or bias current is controlled to cause an amplifier corresponding to an operation mode to operate. For example, Japanese Unexamined Patent Application Publication No. 2005-217562 discloses a configuration for switching a bias voltage to be supplied to an amplifier by using a switch to cause an amplifier corresponding to an operation mode to operate.
The configuration disclosed in Japanese Unexamined Patent Application Publication No. 2005-217562 has a problem in that a voltage drop caused by the on-resistance of the switch occurs when a bias current flows through the switch, which may cause deterioration in the characteristics of the bias circuit.